This application is based on application(s) No. Hei 11-006342 and Hei 11-016790 filed in Japan, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image-recording medium capable of being reused repeatedly wherein a printed material made to adhere to the image-recording medium by image formation in a copying machine, a printer or the like is removable from the image-recording medium.
2. Description of the Related Art
Electrophotographic copying techniques using toners (so called copy simply) are popular now. Image-recording media such as paper and OHP sheets are used in large quantities.
Printed materials printed or copied on such image-recording media are not easily removed. Techniques for removing such printed materials are not yet ready for practical use. It is true that printed materials generated in large quantities in offices are discarded when they become unnecessary.
This is clearly not desirable from the viewpoint of environmental protection and natural resource preservation. Therefore, researches on techniques for reproducing or recycling image-recording media which would otherwise be discarded have been vigorously conducted. U.S. Pat. No. 5,738,759 and EP0601502, for example, disclose methods wherein a swelling layer which swells by absorbing water is formed on the surface of an image-recording medium and images printed on the image-recording medium are removed by swelling the swelling layer with water.
The recording medium swells when immersed in an image-removing solution such as water, so that a volume of the recording medium changes. The printed materials, such as toner, printed on the recording medium do not swell generally in the image-recording solution. Therefore, a shearing force generates at an interface between the recording medium and the printed materials as the volume of the recording medium changes. As a result, the printed materials become easy to separate from the recording medium. When physical frictional force, such as brushing, is applied to the printed materials, they can be removed completely.
However, the above techniques have problems on insufficient removal of printed materials and durability and can not satisfy the technical properties such as removing properties of printed materials and durability required by a recyclable recording medium.
An object of the present invention is to provide a recyclable image-recording medium excellent in both printed image-removing properties and durability.
Another object of the present invention is to provide a recyclable image-recording medium with high durability, in which printed materials, such as toner, can be removed speedily.
The above object can be achieved by a recyclable recording medium comprising;
a base member,
a surface layer comprising a water-swelling resin, and having a thickness of 3 to 30 xcexcm;
a saturated swelling amount in the direction of thickness is 4 to 25 xcexcm when the recyclable recording medium is immersed in an aqueous medium.